I do similar things selling character's upgraded adventuring gear that seldom has a mechanical benefit. Like the collapsible ten foot pole that had special attachments to let them maybe do things, small cup to sample something liquid at ten feet, small wedge tool like crowbar to pry at range etc.
The one player goes and gets stuff from a leather worker halfling who sells several kits worked into her carry bags so she had a survival kit belt, and healer kit bandoleer and sells many unique leather goods , satchels etc that and adventurer might like and see as cool but have no real game benefit other than being cool.
Hey, it's one hundred percent possible! All you need is discipline, a good platform to do it and, I think, a bit of luck. First of all, forget about ebay or amazon. These are large companies, and you can make a good profit by buying goods there only if you are already a medium or large company. Secondly, I think you'd better think about toddler boy winter clothes, which can be found on
thetrendytoddlers.com . I always buy there and there have been no problems yet.